Method for re-entry of damaged well pipe



March 29, 1966 METHOD Filed Aug- 9. 1963 D. A. NoR'rI-I 3,242,985

FOR REI-ENTRY OF DAMAGED WELL PIPE 4 Sheets-Sheet 1 ATTORNEY.

March 29, 1966 D. A. NORTH 3,242,985

METHOD FOR RE-ENTRY OF DAMAGED WELL PIPE Filed Aug. 9, 1963 4 Sheets-Sheet 2 I N VEN TOR.

DANIEL A. ORTH, Byvwd ATTORNEY D. A. NORTH METHOD FOR RE-ENTRY OF DAMAGED WELL PIPE March 29, 1966 TTO RN EY.

4 Sheets-Sheet 5 DAN|EL A.NORTH,|NVENTOR v BY WHIP STOCK COLLAR omi-:NTING sus March 29, 1966 D. A. NORTH METHOD FOR 11E-ENTRY oF DAMAGED WELL PIPE 4 Sheets-Sheet 4 Filed Aug. 9, 1963 FIG. 8.

INDEX DETECTOR SECTION /sLEEvE LEAD SHIELD sEcTloN 3 5 sul DE s LOT GUIDE Lus `NEuTRoN souRcE INVENTOR.

DA NIEL A NO RTH JWM/M ATTORNEY.

3,242,985 METHOD FOR R11-ENTRY 0F DAMAGED WELL PIPE Daniel A. North, Midland, Tex., assigner, by mesne assignments, to Esso Production Research Company,

Houston, Tex., a corporation of Delaware Filed Aug. 9, 1963, Ser. No. 301,058 4 Claims. (Cl. 1166-4) The present invention generally relates to method for re-entering damaged casing pipe in a well. More particularly it concerns method for effecting such re-entry in order to remove any iish such as drill pipe or other tubular goods, as well as to prepare the re-entered parted or damaged casing for running of smaller diameter casing to restore use of the original borehole.

Frequently, well casing pipe parts and/ or collapses during drilling or production operations, and when this occurs, much oort and money are expended in an attempt to restore the former communications through the damaged casing pipe. Very often such communication is never re-established and the hole is lost.

Once oil field casing collapses or parts, it is conventional procedure to attempt to mill or drill through the damaged section and hope that the lower section of pipe below the damaged section is still in alignment with the upper casing above the damaged zone. Occassionally it is possible to drill into the casing below the damaged zone with no difficulty, remove any fish in the lower section of casing and run a small remedial string of casing if one is needed. Generally however, the lower Section of casing is missed and the drilling oftentimes results in cutting a new hole alongside the lower section of casing. When this occurs, the new hole is filled with cement and drilling is resumed in a trial and error attempt to communicate to the inside of the lower section of casing.

Further, frequently the casing is uncemented in the interval where the collapsed or parted damage occurs, In this instance after failing to communicate into the lower section of casing, both the lower and upper sections must be immobilized by cement. The upper section is immobilized by perforating the casing 50-100 feet above the damaged zone, setting a packer or tubular goods between these two depths, and displacing cement into the annular space between the original borehole and the casing.' After drilling out, tubing or small drill pipe may be washed down between the lower section of casing below the damaged zone and the original borehole. Cement may then be circulated back into the upper casing section and the tubular goods removed.

The hole is slowly `and carefuly redrilled using light bit weight and because the material surrounding the pipe is less dense or less hard than the formation material,

the bit will preferentially drill in a part of the old original hole and immediately adjacent to the immobilized lower section of casing below the damaged zone.

Prior to employing the re-entry technique of Athe invention, it is necessary to determine whether the drill pipe is outside of or within the casing pipe and to obtain this information, a well known radioactivity pipe locator technique is employed. In this technique, which has been used in the past to orient the tiring direction of gun perforators, a tool containing a source and detector of radiation, either or both of which are focused or collimated, respectively, is rotated through a 360 traverse and the angular positions of adjacent pipe strings are detected and recorded relative to the location of the tool. When used with gun perforating, the angular positions of the pipe strings are established relative to the angular direction of pipe detection which is iixed relative to the tiring direction of the perforator. This tool and its use United States Patent O FCice in gun perforating operations is described in U.S. Patent application Serial No. 780,524, led December 15, 1958, by Henry S. Arendt, entitled Method and Apparatus for Operating in Wells. Additional descriptions of similar tools and their operations are found in the Composite Catalog of Oil Field Equipment and Services, 24th ed., 1961-62, vol. 3, page 4862, under the title Oriented Perforating and the 25th ed., 1962-63, Vol. 2, page 2938, under the title Nuclear Orientor.

The method of the invention provides a novel way to gain re-entry to the lower section of casing pipe once it has been established through the pipe locator technique just described that the drill pipe lies outside of the casing pipe. In essence, this method comprises milling a window in the lower section of casing pipe using a whipstoclr atxed to the lower end of the drill string and properly oriented with respect to a radioactivity pipe locator tool similar to the ones used and described above, but modified to operate with the directionally fixed whipstock. After the window is milled, any fish in the lower section of casing may be removed before running through the upper and lower sections of casing pipe and through the new by-pass pasageway, a new, smaller diameter casing pipe and ccmenting i-t in place. A special orienting sub, connected in the drill pipe, cooperates with means on the modified pipe locator tool to tix the position of the tool with respect to the position of the whipstock.

Thus, a primary object of the present invention is to provide an improved, positive method for obtaining reentry into damaged casing pipe in order to remove fish and/ or to set a new casing string after re-entry.

The above object and other objects and advantages of this invention will become more apparent in the following, more detailed description of the invention when taken with the drawings in which:

FIGS. l to 6 are vertical, partly sectional views of a borehole illustrating sequential steps of the method of the invention;

FIG. 7 is an isometric view of a radioactivity pipe locator device for use with `the method of the invention; and

FiG. 8 is a vertical, partly sectional view of an orienting sub used with the pipe locator of FIG. 7.

In FiG. l is shown a conventional surface well-head apparatus 1t) from which is suspended a conductor casing pipe 11 cemented in place by cement 12 and a deeper set casing pipe 13 cemented in place by cement 14. Casing pipe 13 has parted and collapsed as indicated at 15, and the lower portion of a drill pipe 16 is shown contained partly within the lower fish portion 17 of casing 13, and in the open hole 13 below the lower end of parted casing 13.

As seen in FlG. 2, a tubular string such as drill pipe 19 is lowered through the upper part 26 of damaged casing pipe 13, and an attempt is made to drill into the lower iish portion 17 of the casing pipe. Drill pipe 19 drills to a preselected or predetermined depth sutiicient to insure that the drill pipe has either entered the lower portion 17 of the casing pipe or is positioned alongside it.

In this position, as seen in FIG. 3, a pipe locator tool 21 is suspended in drill pipe 19 by a conductor cable 22 connected to a surface recorder 23. Tool 21 (or pipe 19 if tool 21 is ixed immovably within pipe 19) is then rotated 360. If, as is shown in FIG. 3, drill pipe 19 is positioned alongside the fish portion lof casing pipe 17, then `the presence of casing pipe 17 will be indicated on recorder 23. If, however, drill pipe 21 drilled into and was positioned within the casing pipe 17, then no indication of pipe adjacent to the pipe locator tool 21 would be recorded on recorder 23 when the pipe locator tool 21 was rotated. In this latter event, new casing pipe would be run and the communication re-established through known procedures.

As an example of this technique in an actual eld oper-ation, a well had 8% inch casing pipe part at 3,152 feet with the top joint of the lower sh collapsed With its top at 3,154 feet. The pipe locator survey was run after 7% inch washpipe and 77/8 rotary shoe had drilled to about 3,192 feet (past a casing collar at 3;l81 feet). Two and one-half inch tubing was then run to 3,192 feet and the pipe locator survey clearly indicated that the 21/2 inch tubing string was outside the 85/3 inch casing pipe fish.

When it is determined that drill pipe 19 is not within casing pipe 17, pipe locator tool 21 and drill pipe 19 are removed from .the well. New cement may then be placed adjacent the lower section of casing pipe 17 to immobilize it as seen in FIG. 3A. The drill pipe 19, having been raised to above the uppermost level of the new cement, is then used, together with the bit on the end thereof, to drill through the new cement after it has set up to below the uppermost end of the lower section of damaged casing pipe 17 as seen in FIGS. 3B and 3C. The first pipe locator means is then lowered to the lower end of the drill pipe and it is operated to determine whether the drill pipe and drill bit are outside of or inside of the lower section of casing pipe. When it has been determined that the drill pipe is outside of the lower section of casing pipe, the drill `pipe and first pipe locator -means are removed from the well. Referring to FIG. 4, on the lower end of drill pipe 19 is arranged an orienting sub 27, seen in detail in FIG. 8, just above bit 24. A Whipstock 28 is fastened to bit 24 by shear pins. Then the drill pipe with its orienting sub and whipstock is run through the upper parted portion 20 of casing pipe 13 to the bottom of the newly drilled hole 29.

Sub 27 is formed with a cam surface Si) and groove 31, designed to position a pipe locator tool 32 shown in FIG. 7. Tool 32 includes a collimated detector 33 and a focused source of radiation 34 separated by shielding means 35. A positioning lug 36 on tool 32 is aligned with the collimated detector or focused .source in a fixed or known angular position relative thereto. The face of the Whipstock 28 is aligned with groove 31 of sub 27 or in a fixed, predetermined angular position relative to the angular position of groove 31, and if desired an indexing line 37 may be marked on sub 27 to facilitate orientation of the subs groove with the face of whipstock 2S.

Pipe locator tool 32 is lowered through drill pipe 19 on a conductor wire line 39 connected to a surface recorder until cam surface 3i) guides lug 36 into groove 31 in sub 27. Then drill pipe 19 is raised off bottom to permit rotation of the drill pipe and drill pipe 19 is rotated to permit pipe locator tool 32 to detect and locate casing pipe 17 relative to the face of whipstock 2S which is then aligned with the casing pipe 17. The drill pipe 19 is then lowered and the w-hipstock 23 firmly imbedded in the cement 14. Slack-off of additional weight of drill pipe 19 shears Ithe mill 24 free of the now oriented whipstock and the drill pipe is free to turn the mill against the side of the casing 17. A window 40 is cut in the casing pipe 17 as shown in FIG. 5 by means of the drill pipe A19 and the mill 24. The new by-pass passage is then preferably reamed and enlarged and smoothed out as desired. Any fish in the lower part of the now communicated-to casing 17, such as a drill pipe fish 16, then may be removed by conventional fishing techniques.

As seen in FIG. 6, a smaller string of new casing 41 is run through the larger casing 26 and lower portion thereof 17, through the by-pass passage 29. Although not shown, the smaller casing then is cemented in place by conventional cementing techniques.

Having fully described the method, apparatus, objects, and operation of my invention, I claim:

1. A .method for re-entering the lower, undamaged section of a damaged casing pipe arranged in a well 'bore and re-establishing communication between the lower and upper undamaged sections of said casing pipe comprising the steps of:

drilling through the undamaged, upper section of sai damaged casing pipe and beyond to a preselected depth below the upper end of said lower section of casing pipe with a drill pipe and drill bit attached to the end thereof;

lowering a first pipe locator means provided with a selected, angular direction of pipe detection to the lower end of said drill pipe, said pipe locator means being adapted, when operated, to detect the angular location of another pipe string relative to the position of said drill pipe;

operating said first pipe locator means and detecting the lower section of said casing pipe;

removing said first pipe locator means from said drill Pipe; placing cement adjacent the lower section of said casing pipe to immobilize it and raising said drill pipe to a position above the upper level of said cement; waiting sufficient time to permit said cement to set up; drilling a portion of a bypass passageway through said new cement to a preselected depth below the upper end of said lower section of casing pipe with said rill pipe and drill bit attached to the end thereof; lowering said first pipe locator means to the lower end of said drill pipe;

operating said first pipe locator means to detect said lower section of casing pipe; removing said drill pipe and said first pipe locator means from said bypass passageway drilled in said new cement and said upper section of casing pipe;

arranging a whipstock on the lower end of said drill pipe, the angular direction of the face of which is fixed on said drill pipe;

running said drill pipe and whipstock through the upper section of said drill pipe into the drilled portion of said bypass passageway; lowering and positioning in the lower end of said drill pipe a second pipe locator means provided with a selected angular direction of pipe detection, the angular direction of the face of said whipstock being in za fixed relationship to the angular direction of pipe detection of said second pipe locator means;

operating said second pipe locator means to determine the direction of the lower section of said casing pipe;

directing the face of said whipstock toward the lower section of said casing pipe as determined by said second pipe locator means, said whipstock being set in its oriented position by slacking off drill pipe weight;

removing said second pipe locator means from said drill plee;

completing drilling said bypass passageway and milling a window in the lower section of said casing pipe with said drill pipe and drill bit directed by said whipstock;

removing said drill pipe and whipstock from said drilled,

bypass passageway leading to said window in said casing pipe;

running through said upper section of casing pipe and said bypass passageway into said window and said lower section of casing pipe a smaller string of caslng pipe; and

then cementing said smaller casing pipe in said bypass passageway.

2. A method for re-entering the lower, undamaged section of damaged casing pipe and re-establishing communication between the upper and lower undamaged sections of casing pipe comprising the steps of:

drilling through the undamaged, upper section of said damaged casing pipe and beyond to a preselected depth below the upper end of said lower section of casing pipe with a drill string and drill bit attached to the lower end thereof;

lowering a first pipe locator means provided with a selected, angular direction of pipe detection to the bottom of said drill pipe;

said first pipe locator means being adapted to detect the angular location of said lower section of casing pipe relative to the location of said drill pipe when operated; operating said first pipe locator means and detecting the lower section of said casing pipe to establish that a portion of a bypass passageway has been drilled alongside the lower section of said casing pipe;

removing said drill pipe and said first pipe locator means from said well;

arranging a whipstock on the lower end of said drill pipe, the angular direction of the face of which is fixed;

running said drill pipe and whipstock through the upper section of said casing pipe and into the drilled portion of said bypass passageway; flowering and positioning in said driill pipe a second pipe locator means provided with a selected, angular direction of pipe detection, said second pipe locator means being adapted to locate the angular position of said lower section of casing pipe relative to the location of said drill pipe when said second pipe locator means is actuated, the angular direction of the face of said whipstock Ibeing fixed relative to the angular direction of pipe detection of said second pipe locator means;

directing the face of said whipstock toward the lower section of said casing pipe as determined by said second pipe locator means;

setting the whipstock in its oriented position;

removing said second pipe locator means from said drill plpe;

drilling with said drill pipe and drill bit attached to the lower end thereof and continuing said bypass passageway and milling out a window in the lower section of said casing pipe;

removing said drill pipe and said whipstock from said bypass passageway and the upper section of said casing pipe;

running in said upper section of casing pipe and said bypass passageway and into said window in the lower section of said casing pipe a smaller string of casing pipe; and

then cementing said smaller casing pipe in said bypass passageway.

3. A method for re-entering the lower, undamaged section of a damaged casing pipe arranged in a well bore comprising the steps of:

drilling through the undamaged, upper section of said damaged casing pipe and beyond to a preselected depth below the upper end of said lower section with a drill pipe and drill bit attached to the lower end thereof;

lowering a first pipe locator means provided with a selected, angular direction of pipe detection to the lower end of said drill pipe, said pipe locator means being adapted, when operated, to detect the angular location of another pipe string relative to the position of said drill pipe;

operating said first pipe locator means and detecting the lower section of said damaged casing pipe; removing said first pipe locator means from said drill Plpe; placing cement adjacent the lower section of said casing pipe to immobilize it and at the same time, raising said drill pipe to a position above the upper level of said cement;

waiting sufficient time to permit said cement to set up;

drilling a portion of a bypass passageway through the upper section of said casing pipe and through said new cement to a preselected depth Ibelow the upper end of said lower section o'f casing pipe with said drill pipe and drill bit attached to the lower end thereof;

lowering vsaid first pipe locator means to the lower end of said drill pipe;

operating said first pipe locator means to detect said lower section of casing pipe; t

removing said drill pipe and said first pipe locator means from said bypass passageway drilled in said new cement and said upper section of casing pipe;

arranging a whipstock on the lower end of said drill pipe, the angular direction of the face of which is fixed on said drill pipe;

running said drill pipe and whipstock through the upper section of said drill pipe into the drilled portion of said bypass passageway;

lowering and positioning in the lower end of said drill pipe a second pipe locator means provided with a selected angular direction of pipe detection, the angular direction of the face of said whipstock being in a fixed, angular relationship to the fixed, angular direction of pipe detection of said second pipe locator means;

operating said second pipe locator rneans to determine the direction of the lower section of said casing pipe;

directing the face of said whipstock toward the lower section of said casing pipe as determined by said second pipe locator means, said whipstock being set in its oriented position by slacking off drill pipe weight;

removing said second pipe locator means from said drill pipe; and

milling a window in the lower section of said casing pipe with said drill pipe directed by said whipstock.

4. A method for re-entering the lower, undamaged section of damaged casing pipe and re-establishing communication between the upper and lower undamaged sections of casing pipe comprising the steps of:

drilling through the undamaged, upper section of said damaged casing pipe and beyond to a preselected depth below the upper end of said lower section of casing pipe with a drill string and drill bit attached to the lower end thereof;

lowering a first pipe locator means provided with a selected, angular direction of pipe detection to the bottom of said drill pipe;

said first pipe locator means being adapted to detect the angular location of said lower section of casing pipe relative to the location of said drill pipe when operated;

operating said first pipe locator means and detecting the lower section of said casing pipe to establish that a portion of said bypass passageway has been drilled alongside the lower section of said casing pipe;

removing said drill pipe and said first pipe locator means from said well;

arranging a whipstock on the lower end of said drill pipe, the angular direction of the face of which is running said drill pipe and whipstock through the upper section of said casing pipe and into the drilled portion of said bypass passageway;

lowering and positioning in said drill pipe a second pipe locator means provided with a selected, angular direction of pipe detection, said second pipe locator means being adapted to locate the angular position of said lower section of casing pipe relative to the location of said drill pipe when said second pipe locator means is actuated, the angular direction of the face of said whipstock being fixed relative to the angular direction of pipe detection of said second pipe locator means;

directing the face of said whipstock toward the lower section of said casing pipe as determined by said second pipe locator means;

7 setting the Whipstock in its oriented position;

removing said second pipe locator means from said drill pipe; and

drilling with said drill pipe and drill bit attached to the lower end thereof and continuing said bypass passageway and milling out a window in the lower section 0f said casing pipe.

References Cited by the Examiner UNlTED STATES PATENTS 8 2,691,507 10/1954 Brown l66-ll7.5 2,734,580 2/1956 Layne 166-14 2,804,147 8/1957 Pistole et al 166-l4 3,104,709 9/1963 Konneday et al. l66-55.1

OTHER REFERENCES Anderson, Alexander et al.: Protecting Oil Sands by Directional Drilling. In The Petroleum Engineer. 7(12) pp. 36 and 37. August 1936. TN 8,60. P4.

CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, D. H. BROWN, Assistant Examiners. 

4. A METHOD FOR RE-ENTERING THE LOWER, UNDAMAGED SECTION OF DAMAGED CASING PIPE AND RE-ESTABLISHING COMMUNICATION BETWEEN THE UPPER AND LOWER UNDAMAGED SECTIONS OF CASING PIPE COMPRISING THE STEPS OF: DRILLING THROUGH THE UNDAMAGED, UPPER SECTION OF SAID DAMAGED CASING PIPE AND BEYOND TO A PRESELECTED DEPTH BELOW THE UPPER END OF SAID LOWER SECTION OF CASING PIPE WITH A DRILL STRING AND DRILL ATTACHED TO THE LOWER END THEREOF; LOWERING A FIRST PIPE LOCATOR MEANS PROVIDED WITH A SELECTED, ANGULAR DIRECTION OF PIPE DETECTION TO THE BOTTOM OF SAID DRILL PIPE; SAID FIRST PIPE LOCATOR MEANS BEING ADAPTED TO DETECT THE ANGULAR LOCATION OF SAID LOWER SECTION OF CASING PIPE RELATIVE TO THE LOCATION OF SAID DRILL PIPE WHEN OPERATED; OPERATING SAID FIRST PIPE LOCATOR MEANS AND DETECTING THE LOWER SECTION OF SAID CASING PIPE TO ESTABLISH THAT A PORTION OF SAID BYPASS PASSAGEWAY HAS BEEN DRILLED ALONGSIDE THE LOWER SECTION OF SAID CASING PIPE; REMOVING SAID DRILL PIPE AND SAID FIRST PIPE LOCATOR MEANS FROM SAID WELL; ARRANGING A WHIPSTOCK ON THE LOWER END OF SAID DRILL PIPE, THE ANGULAR DIRECTION OF THE FACE WHICH IS FIXED; RUNNING SAID DRILL PIPE AND WHIPSTOCK THROUGH THE UPPER SECTION OF SAID CASING PIPE AND INTO THE DRILLED PORTION OF SAID BYPASS PASSAGEWAY;= LOWERING AND POSITIONING IN SAID DRILL PIPE A SECOND PIPE LOCATOR MEANS PROVIDED WITH A SELECTED, ANGULAR DIRECTION OF PIPE DETECTION, SAID SECOND PIPE LOCATOR MEANS BEING ADAPTED TO LOCATE THE ANGULAR POSITION OF SAID LOWER SECTION OF CASING PIPE RELATIVE TO THE LOCATION OF SAID DRILL PIPE WHEN SAID SECOND PIPE LOCATOR MEANS IS ACTUATED, THE ANGULAR DIRECTION OF THE FACE OF SAID WHIPSTOCK BEING FIXED RELATIVE TO THE ANGULAR DIRECTION OF PIPE DETECTION OF SAID SECOND PIPE LOCATOR MEANS; DIRECTING THE FACE OF SAID WHIPSTOCK TOWARD THE LOWER SECTION OF SAID CASING PIPE AS DETERMINED BY SAID SECOND PIPE LOCATOR MEANS; SETTING THE WHIPSTOCK IN ITS ORIENTED POSITION; REMOVING SAID SECOND PIPE LOCATOR MEANS FROM SAID DRILL PIPE; AND DRILLING WITH SAID DRILL PIPE AND DRILL BIT ATTACHED TO THE LOWER END THEREOF AND CONTINUING SAID BYPASS PASSAGEWAY AND MILLING OUT A WINDOW IN THE LOWER SECTION OF SAID CASING PIPE. 